An erasing device capable of erasing an image on a sheet is conventionally known. With this erasing device, the image is erased and then the erased surface of the sheet is scanned by a scanning unit. A conveying path branches off at a position downstream in sheet conveying direction from the scanning unit. A first branch path is connected to a first discharging unit, and a second branch path is connected to a second discharging unit. When it is determined that there is no unerased part on the erased surface, the erasing device sorts the sheet from the scanning unit to the first branch path and discharges the sheet to the first discharging unit. When it is determined that there is an unerased part on the erased surface, the erasing device sorts the sheet from the scanning unit to the second branch path side and discharges the sheet to the second discharging unit.
Since such an erasing device is provided at places like an office, there is a need for size reduction of the device.